public OrderProduct(Product product, int count)
 {
     Product     = product;
     Count       = count;
     AmountValue = Product.AmountValue;
     Product.UpdateStoreCountTo(Math.Abs(Count));
 }
        public OrderProduct(Product product, int count, decimal amountValue)
        {
            Product = product;
            Count   = count;
            Product.UpdateStoreCountTo(Math.Abs(Count));

            if (amountValue <= 0)
            {
                throw new ArgumentException($"{nameof(amountValue)} cannot be zero or negative.", nameof(amountValue));
            }

            AmountValue = amountValue;
        }